Intrahepatic hepatitis B virus covalently closed circular DNA can be a predictor of sustained response to therapy

Efficacy and in vitro pharmacological assessment of novel N-hydroxypyridinediones as hepatitis B virus ribonuclease H inhibitors

We previously reported N-hydroxypyridinedione (HPD) compounds with mid-nanomolar efficacy and selectivity indexes around 300 against hepatitis B virus (HBV) replication. However, they lack pharmacological evaluation. Here, we report in vitro anti-HBV efficacy, cytotoxicity, and pharmacological characterization of 29 novel HPDs within seven subgroups. The best two compounds had EC50s of 61 and 190 nM and selectivity indexes of 526 and 1,071. Compounds with one halogen on the major R group were most effective and compounds with large ether R groups were most cytotoxic. Compounds were not cytotoxic in primary human hepatocytes. All compounds were freely soluble in pHs reflecting plasma (7.4) and the gastrointestinal tract (5 and 6.5). Almost all highly soluble compounds were passively permeable at pH 5.0 and 7.4. Only 2 of 11 compounds tested were likely to be effluxed by p-glycoprotein. The most potent HPDs inhibited HBV replication over human ribonuclease H1 activity by 10-fold. Four of 19 compounds inhibited CYP2D6 >50%, but their CYP2D6 IC50s were >8× higher than their anti-HBV EC50. No compound substantially inhibited CYP3A4. Thirteen of 15 compounds had human microsomal half-lives >30 min with medium to low rates of intrinsic clearance. Eleven of 12 compounds bound plasma proteins by ≥80%; however, effects against HBV replication for only one would likely be physiologically relevant. These results identify two lead candidate HPDs with pharmacological characteristics resembling commercially available drugs that are suitable for in vivo pharmacological and efficacy studies.

Prediction of cccDNA dynamics in hepatitis B patients by a combination of serum surrogate markers

Quantification of intrahepatic covalently closed circular DNA (cccDNA) is a key for evaluating an elimination of hepatitis B virus (HBV) in infected patients. However, quantifying cccDNA requires invasive methods such as a liver biopsy, which makes it impractical to access the dynamics of cccDNA in patients. Although HBV RNA and HBV core-related antigens (HBcrAg) have been proposed as surrogate markers for evaluating cccDNA activity, they do not necessarily estimate the amount of cccDNA. Here, we employed a recently developed multiscale mathematical model describing intra- and intercellular viral propagation and applied it in HBV-infected patients under treatment. We developed a model that can predict intracellular HBV dynamics by use of extracellular viral markers, including HBsAg, HBV DNA, and HBcrAg in peripheral blood. Importantly, the model prediction of the amount of cccDNA in patients over time was confirmed to be well correlated with the data for quantified cccDNA by paired liver biopsy. Thus, our method combining classic and emerging surrogate markers enables us to predict the decay dynamics of cccDNA in patients undergoing treatment.

HBV pregenome RNA as a predictor of spontanous HBeAg seroconversion in HBeAg-positive chronic hepatitis B patients

BACKGROUND

Previous studies have indicated that HBV pregenome RNA (HBV pgRNA) could predict HBeAg seroconversion among the chronic hapatitis B (CHB) patients treated with pegylated interferon (Peg-IFN) or nucleos(t)ide analogues (NAs). However, the data about the prediction of HBV pgRNA for spontaneous HBeAg seroconversion is limited.

METHODS

One hundred thirteen CHB patients with HBeAg-positive in the immune active phase were followed up for 76 weeks without antiviral treatment. Based on the laboratory test results of liver function, HBeAg, anti-HBe, and HBV DNA at week 76, patients were assigned to two groups: spontaneous HBeAg seroconversion (group A, n = 18) and non-spontaneous HBeAg seroconversion group. Among the latter group, 36 patients were selected as controls (group B, n = 36).

RESULTS

At week 12, between group A and group B, there was a significant difference in the level of HBV pgRNA (group A 6.35 ± 1.24 log10 copies/ml and group B 7.52 ± 0.79 log10 copies/ml, P = 0.001), and the difference enlarged at week 28. The receiver operating characteristic curves (AUROCs) of the HBV pgRNA level and the ∆HBV pgRNA at week 28 were 0.912 (P = 0.001, 95% CI: 0.830-0.994), and 0.934 (P = 0.001, 95% CI: 0.872-0.996), respectively. The optimal cutoffs of HBV pgRNA and the reduction from baseline (∆HBV pgRNA) at week 28 for spontaneous HBeAg seroconversion prediction were 5.63 log10 copies/ml and 1.85 log10 copies/ml, respectively. The positive predictive value and negative predictive value of HBV pgRNA and ∆HBV pgRNA at week 28 were 86.7% and 87.2%, 87.5% and 89.5%, respectively. And the combination of the HBV pgRNA level and the HBV pgRNA decreased could provide better prediction.

CONCLUSIONS

HBV pgRNA is a sound predictor for spontaneous HBeAg seroconversion among the CHB patients in immune active phase. Dynamic monitoring of HBV pgRNA is helpful for clinical treatment decision.

A novel hepatitis B virus capsid assembly modulator QL-007 inhibits HBV replication and infection through altering capsid assembly

The core protein allosteric modulators (CpAMs) have shown great potential as highly effective antiviral drugs against hepatitis B virus (HBV) in preclinical studies and clinical trials. In this study, we evaluated a small molecule compound called QL-007, which could potentially influence capsid assembly, using HBV replicated and susceptible cell models as well as mice infected with rAAV-HBV. QL-007 significantly inhibited HBV replication in a dose-dependent manner both in vitro and in vivo, resulting in significant decreases in HBV DNA, 3.5 kb HBV RNA and HBeAg. Furthermore, QL-007 not only induced the formation of misshaped Cp149 capsids but also possessed the capability to disassemble HBV capsids. It is noteworthy that QL-007 effectively reduced cccDNA biosynthesis in de novo infections. Mechanistically, QL-007 blocked the encapsidation of pgRNA and induced aberrant polymers assembly at concentrations ≥100 nM, while having no impact on the stability of core proteins. In conclusion, our findings underscore the potential of QL-007 as an effective agent against HBV replication and introduce it as a novel CpAM for the antiviral treatment of chronic hepatitis B.

Drug Discovery Study Aimed at a Functional Cure for HBV

Hepatitis B virus (HBV) causes acute and, most importantly, chronic hepatitis B worldwide. Antiviral treatments have been developed to reduce viral loads but few patients with chronic hepatitis B (CHB) achieve a functional cure. The development of new therapeutic agents is desirable. Recently, many novel agents have been developed, including drugs targeting HBV-DNA and HBV-RNA. This review provides an overview of the developmental status of these drugs, especially direct acting antiviral agents (DAAs). Serological biomarkers of HBV infection are essential for predicting the clinical course of CHB. It is also important to determine the amount and activity of covalently closed circular DNA (cccDNA) in the nuclei of infected hepatocytes. Hepatitis B core-associated antigen (HBcrAg) is a new HBV marker that has an important role in reflecting cccDNA in CHB, because it is associated with hepatic cccDNA, as well as serum HBV DNA. The highly sensitive HBcrAg (iTACT-HBcrAg) assay could be a very sensitive HBV activation marker and an alternative to HBV DNA testing for monitoring reactivation. Many of the drugs currently in clinical trials have shown efficacy in reducing hepatitis B surface antigen (HBsAg) levels. Combination therapies with DAAs and boost immune response are also under development; finding the best combinations will be important for therapeutic development.

Virological Treatment Monitoring for Chronic Hepatitis B

More than 250 million people worldwide are currently infected with hepatitis B, despite the effectiveness of vaccination and other preventive measures. In terms of treatment, new therapeutic approaches are rapidly developing, promising to achieve the elimination of infected cells and the complete cure of infection. The on-treatment monitoring of these innovative antiviral treatments will require the implementation of new virological tools. Therefore, new biomarkers are being evaluated besides the traditional virological and serological assays in order to obtain information on different steps of the viral replication cycle and to monitor response to therapy more accurately. The purpose of this work is to describe both standard and innovative tools for chronic hepatitis B treatment monitoring, and to analyse their potential and feasibility.

DNA Repair Factor Poly(ADP-Ribose) Polymerase 1 Is a Proviral Factor in Hepatitis B Virus Covalently Closed Circular DNA Formation

The biogenesis and eradication of HBV cccDNA have been a research priority in recent years. In this study, we identified the DNA repair factor PARP1 as a host factor required for the HBV de novo cccDNA formation.

Prevention of HBV Reactivation in Hemato-Oncologic Setting during COVID-19

Onco-hematologic patients are highly susceptible to SARS-CoV-2 infection and, once infected, frequently develop COVID-19 due to the immunosuppression caused by tumor growth, chemotherapy and immunosuppressive therapy. In addition, COVID-19 has also been recognized as a further cause of HBV reactivation, since its treatment includes the administration of corticosteroids and some immunosuppressive drugs. Consequently, onco-hematologic patients should undergo SARS-CoV-2 vaccination and comply with the rules imposed by lockdowns or other forms of social distancing. Furthermore, onco-hematologic facilities should be adapted to new needs and provided with numerically adequate health personnel vaccinated against SARS-CoV-2 infection. Onco-hematologic patients, both HBsAg-positive and HBsAg-negative/HBcAb-positive, may develop HBV reactivation, made possible by the support of the covalently closed circular DNA (cccDNA) persisting in the hepatocytic nuclei of patients with an ongoing or past HBV infection. This occurrence must be prevented by administering high genetic barrier HBV nucleo(t)side analogues before and throughout the antineoplastic treatment, and then during a long-term post-treatment follow up. The prevention of HBV reactivation during the SARS-CoV-2 pandemic is the topic of this narrative review.

Significance of T-Cell Subsets for Clinical Response to Peginterferon Alfa-2a Therapy in HBeAg-Positive Chronic Hepatitis B Patients

Introduction

The adaptive immune response may reflect the immunomodulatory efficacy during peginterferon alfa-2a (PEG-IFN α-2a) treatment in chronic hepatitis B (CHB) patients. We evaluated the predictive efficiency of T-cell subsets on patient's response to PEG-IFN α-2a treatment.

Methods

The proportions of CD8+PD-1+, CD8+Tim-3+ and CD4+CD25high T-cells were measured at baseline and week 52 in CHB patients who underwent PEG-IFN α-2a treatment. The proportions of T-cell subsets were compared among different responders and non-responders (determined by biochemical, serological, and virological responses).

Results

The baseline proportions of the three T-cell subsets were significantly higher in CHB patients (65 cases) than in healthy controls (28 cases), while the proportions declined significantly after 52 weeks of PEG-IFN treatment. Responders (ALT < 40 IU/L, 89.2% [58/65]; HBV DNA < 2.7 log10 IU/ml, 66.2% [43/65]; and HBeAg seroconversion [SR], 53.9% [35/65]) experienced more pronounced declines in the proportion of T-cell subsets compared to non-responders. In particular, the baseline proportions of CD4+CD25high T-cells displayed significant difference between SR and non-SR groups. The stepwise logistic regression analysis identified that CD4+CD25high T-cells combined with baseline HBV DNA and ALT can predict SR and CR (ALT < 40 IU/L, HBV DNA < 2.7 log10 IU/mL and HBeAg seroconversion) after 52 weeks of PEG-IFN treatment with high accuracy.

Conclusion

PEG-IFN therapy induces significant declines in the proportion of some key T-cell subsets in HBeAg-positive patients. The model constructed with CD4+CD25high T-cells combined with ATL and HBV DNA may help to predict the efficacy of PEG-IFN α-2a therapy.

Besifovir therapy improves hepatic histology and reduces covalently closed circular DNA in chronic hepatitis B patients

BACKGROUND AND AIM

Besifovir dipivoxil maleate (BSV) was reported to have comparable antiviral efficacy and superior renal and bone safety to tenofovir disoproxil fumarate (TDF) in chronic hepatitis B (CHB) patients. The present study aims to evaluate changes of liver histology and intrahepatic covalently closed circular DNA (cccDNA) levels by BSV treatment in comparison with TDF therapy.

METHODS

This is a subset study of the phase 3 trial comparing BSV with TDF. Among them, only CHB patients willing to participate in a histologic evaluation study were enrolled. Liver histologic examination and intrahepatic cccDNA quantification were performed.

RESULTS

A total of 46 CHB patients received liver biopsies (BSV, n = 29; TDF, n = 17). After 48 weeks of treatment, virological response rate was comparable between the groups (P = 0.707). Follow-up liver biopsies showed that necroinflammation was significantly improved in the both groups. However, the histological response rate defined as the proportion of subjects whose modified histologic activity index score decreased by ≥ 2 without deterioration in fibrosis was higher in the BSV group than in the TDF group (77.8% vs 36.4%, P = 0.048). The proportion of subjects with Ishak fibrosis score 3 or more decreased from 77.7% to 55.5% in the BSV and that decreased from 72.7% to 45.4% in the TDF group. The intrahepatic cccDNA significantly decreased from baseline after 48 weeks of BSV or TDF treatment (P < 0.001) without intergroup differences (P = 0.349).

CONCLUSIONS

The BSV therapy improves hepatic histology and decreases intrahepatic cccDNA in CHB patients.

Epigenetic reprogramming promotes the antiviral action of IFNα in HBV-infected cells

Chronic hepatitis B virus (HBV) infections remain a health burden affecting ~250 million people worldwide. Thus far, available interferon-alpha (IFNα)-based therapies have shown unsatisfactory cure rates, and alternative therapeutic molecules are still required. However, their development has been hampered because accessible cell models supporting relevant HBV replication and appropriate antiviral activity are lacking. Strategies that reverse epigenetic alterations offer a unique opportunity for cell reprogramming, which is valuable for restoring altered cellular functions in human cell lines. This work aimed to investigate the feasibility of converting HepG2 cells that stably overexpress the HBV entry receptor (sodium/taurocholate cotransporting polypeptide, NTCP) toward IFNα-responsive cells using epigenetic reprogramming. Herein, we showed that an epigenetic regimen with non-cytotoxic doses of the demethylating compound 5-azacytidine restored the anti-HBV action of IFNα in epigenetically reprogrammed HepG2-NTCP-C4 cells, named REP-HepG2-NTCP cells. Thus, a significant inhibition in HBV DNA levels was measured in REP-HepG2-NTCP cells after IFNα treatment. This inhibitory effect was associated with the enhancement of IFNα-mediated induction of critical interferon-stimulated genes (ISGs), which was limited in non-reprogrammed cells. In particular, our data indicated that re-expression of 2’-5’-oligoadenylate synthetase 1 (OAS1) and interferon regulatory factor 9 (IRF9) was the result of an epigenetically driven unmasking of these genes in reprogrammed cells. At last, we evaluated the therapeutic potential of the IFN analog CDM-3008 in REP-HepG2-NTCP cells and demonstrated the efficiency of this chemical compound in triggering ISG induction and HBV inhibition. In summary, this study shows that epigenetic reprogramming promotes the IFNα response in HBV-infected cells and is potentially attractive for cell-based experimental screening of IFN-like compounds.

Serum HBV RNA correlated with intrahepatic cccDNA more strongly than other HBV markers during peg-interferon treatment

BACKGROUND

Serum hepatitis B virus RNA (HBV RNA) has been reported to be a surrogate marker of intrahepatic cccDNA during nucleos(t)ide analogs therapy. However, in HBeAg-positive patients treated with peg-interferon (peg-IFN), whether HBV RNA is superior to other HBV markers in reflecting cccDNA profile is still unclear.

METHODS

Serum HBV RNA, HBcrAg, HBV DNA, and HBsAg were longitudinally assessed among 30 HBeAg-positive patients during 48-week peg-IFN treatment. Besides, intrahepatic cccDNA was detected at baseline and week 48 respectively. Then, the individual correlations between HBV RNA, HBcrAg, HBV DNA, HBsAg, and cccDNA were statistically analyzed.

RESULTS

HBV RNA levels decreased more rapidly in patients with HBeAg seroconversion than those without HBeAg seroconversion. Among all patients, cccDNA correlated better with HBV RNA than with HBcrAg, HBV DNA, and HBsAg at baseline. After 48 weeks peg-IFN treatment, cccDNA still correlated more strongly with HBV RNA than other HBV markers. Further analysis indicated that in patients with HBeAg seroconversion cccDNA strongly correlated with HBV RNA and HBcrAg, whereas not correlate with HBV DNA and HBsAg. While in patients without HBeAg seroconversion, cccDNA highly correlated with HBV RNA and HBV DNA, moderately correlated with HBcrAg, and not correlated with HBsAg.

CONCLUSION

Compared to HBcrAg, HBV DNA, and HBsAg, serum HBV RNA correlated more strongly with intrahepatic cccDNA levels before and after 48-week peg-IFN treatment. The level of serum HBV RNA may be a superior surrogate marker in reflecting the intrahepatic cccDNA profile in HBeAg-positive patients during peg-IFN treatment. Trial registration ClinicalTrials, NCT03546530. Registered 1 January 2015. https://clinicaltrials.gov/ct2/results?cond=&term=NCT03546530 .

Lipid nanoparticles loaded with ribonucleoprotein-oligonucleotide complexes synthesized using a microfluidic device exhibit robust genome editing and hepatitis B virus inhibition

The clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) system has considerable therapeutic potential for use in treating a wide range of intractable genetic and infectious diseases including hepatitis B virus (HBV) infections. While non-viral delivery technologies for the CRISPR/Cas system are expected to have clinical applications, difficulties associated with the clinically relevant synthesis of formulations and the poor efficiency of delivery severely hinder therapeutic genome editing. We report herein on the production of a lipid nanoparticle (LNP)-based CRISPR/Cas ribonucleoprotein (RNP) delivery nanoplatform synthesized using a clinically relevant mixer-equipped microfluidic device. DNA cleavage activity and the aggregation of Cas enzymes was completely avoided under the optimized synthetic conditions. The optimized formulation, which was identified through 2 steps of design of experiments, exhibited excellent gene disruption (up to 97%) and base substitution (up to 23%) without any apparent cytotoxicity. The addition of negative charges to the RNPs by complexing single-stranded oligonucleotide (ssON) significantly enhanced the delivery of both Cas9 and Cpf1 RNPs. The optimized formulation significantly suppressed both HBV DNA and covalently closed circular DNA (cccDNA) in HBV-infected human liver cells compared to adeno-associated virus type 2 (AAV2). These findings represent a significant contribution to the development of CRISPR/Cas RNP delivery technology and its practical applications in genome editing therapy.

Reverse transcriptase droplet digital PCR vs reverse transcriptase quantitative real-time PCR for serum HBV RNA quantification

Serum hepatitis B virus (HBV) RNA is a novel marker reflecting the activity of covalently closed circular DNA. However, the methodology for detecting HBV RNA has been a technical challenge. In this study, the performance of reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) for quantifying HBV RNA was compared with that of reverse transcription quantitative real-time PCR (RT-qPCR) in serum samples collected from treatment-naïve patients with different phases of chronic hepatitis B (CHB). A total of 417 serum samples, including 136 HBeAg-positive CHB and 281 HBeAg-negative CHB were examined. HBV RNA levels measured by RT-ddPCR and RT-qPCR showed a high degree of linearity and quantitative correlation. The limit of detections of RT-ddPCR and RT-qPCR assays were 102 and 103 copies/mL, respectively. Our results also demonstrated that RT-ddPCR was superior to RT-qPCR in terms of its consistency for quantifying HBV RNA across all concentrations. In the HBeAg-positive group, serum HBV RNA levels based on RT-ddPCR were moderately correlated with HBV DNA (r = 0.591, P < .001) and HBsAg (r = 0.502, P < .001). Among patients with HBeAg-negative CHB, serum HBV RNA levels were moderately correlated with HBV DNA (r = 0.603, P < .001) but had weak correlation with HBsAg (r = 0.203, P = .001). In summary, RT-ddPCR could enhance the sensitivity of serum HBV RNA detection, particularly among the HBeAg-negative group with low viral loads. Thus, RT-ddPCR could serve as an optimal method for HBV RNA quantification in clinical practice.

cccDNA Maintenance in Chronic Hepatitis B - Targeting the Matrix of Viral Replication

Chronic hepatitis B is a numerically important cause of cirrhosis and hepatocellular carcinoma, despite an effective prophylactic vaccine and well-tolerated and effective oral antivirals. Both the incapacity of the immune system to clear hepatitis B virus (HBV) infection and the unique replication strategies adopted by HBV are considered key determinants of HBV chronicity. In this regard, the formation of the HBV DNA minichromosome, the covalently closed circular DNA (cccDNA), in the nucleus of infected hepatocytes, is essential not only for the production of all viral proteins but also for HBV persistence even after long-term antiviral therapy. Licensed polymerase inhibitors target the HBV reverse transcriptase activity, control the disease with long-term therapy but fail to eliminate the cccDNA. Consequently, the production of viral RNAs and proteins, including the hepatitis B surface antigen (HBsAg), is not abolished. Novel therapeutic efforts that are in the pipeline for early clinical trials explore novel targets and molecules. Such therapeutic efforts focus on achieving a functional cure, which is defined by the loss of HBsAg and undetectable HBV DNA levels in serum. Since a true cure of HBV infection requires the elimination of the cccDNA from infected cells, comprehension of the mechanisms implicated in cccDNA biogenesis, regulation and stability appears necessary to achieve HBV eradication. In this review, we will summarize the state of knowledge on cccDNA metabolism, focusing on insights suggesting potential weak points of the cccDNA that may be key for the development of therapeutic approaches and design of clinical trials aiming at lowering cccDNA loads and activity.

Host-Directed Antiviral Therapy

Antiviral drugs have traditionally been developed by directly targeting essential viral components. However, this strategy often fails due to the rapid generation of drug-resistant viruses. Recent genome-wide approaches, such as those employing small interfering RNA (siRNA) or clustered regularly interspaced short palindromic repeats (CRISPR) or those using small molecule chemical inhibitors targeting the cellular "kinome," have been used successfully to identify cellular factors that can support virus replication. Since some of these cellular factors are critical for virus replication, but are dispensable for the host, they can serve as novel targets for antiviral drug development. In addition, potentiation of immune responses, regulation of cytokine storms, and modulation of epigenetic changes upon virus infections are also feasible approaches to control infections. Because it is less likely that viruses will mutate to replace missing cellular functions, the chance of generating drug-resistant mutants with host-targeted inhibitor approaches is minimized. However, drug resistance against some host-directed agents can, in fact, occur under certain circumstances, such as long-term selection pressure of a host-directed antiviral agent that can allow the virus the opportunity to adapt to use an alternate host factor or to alter its affinity toward the target that confers resistance. This review describes novel approaches for antiviral drug development with a focus on host-directed therapies and the potential mechanisms that may account for the acquisition of antiviral drug resistance against host-directed agents.

Current practice and contrasting views on discontinuation of nucleos(t)ide analog therapy in chronic hepatitis B

Introduction: Long-term, even indefinite treatment with nucleos(t)ide analogs (NAs) is the current first-line therapy for patients with chronic hepatitis B (CHB), regardless of its histological stage. Guidelines and recommendations on duration and endpoints of NA therapy in CHB are not identical and change over time.Areas covered: The authors review NA discontinuation approaches and views with an emphasis on HBeAg-negative patients based on published studies relevant to the topic, stressing on whether or not the optimal endpoint of HBsAg loss is practically achievable.Expert opinion: Discontinuation of NA therapy in HBeAg-negative noncirrhotic patients has to be considered after long-term effective treatment with controlled liver disease activity, undetectable viremia, and significant decline in serum HBsAg titers. Close post-treatment monitoring is required for early intervention in cases of severe clinical relapse. Immediate retreatment hampers the favorable outcome of HBsAg clearance (functional cure) and should be avoided in transient ALT flares. Predictors of such relapses are still under investigation and include viral and patient factors. For HBeAg-positive noncirrhotic patients, there is wide acceptance of the endpoint of HBeAg seroconversion, after a long consolidation period.

Role of hepatitis B antibody in predicting reactivation of resolved hepatitis B virus infection in leukemia patients

BACKGROUND & AIMS

Quantification of anti-HBs and anti-HBc predicts the risk of HBV reactivation (HBVr) in lymphoma patients receiving rituximab treatment. However, it remains unclear whether the quantification is predictive of HBVr in leukemia patients undergoing immunosuppression.

METHODS

and patients: Clinical and laboratory data of the leukemia patients with resolved HBV infection diagnosed between January 2013 and March 2018 were retrospectively collected. Data series of HBV seromarkers and HBV DNA levels before the patients receiving chemotherapy and/or hematopoietic stem cell transplantation (HSCT) and during follow-up duration were analyzed.

RESULTS

In total, 533 leukemia patients with resolved HBV infection were included. The incidences of HBVr were 5.7% (25/441) and 2.2% (2/92) in patients receiving HSCT and chemotherapy, respectively. In patients receiving HSCT, acute lymphoid leukemia had a significantly higher incidence of HBVr than acute myeloid leukemia (8.9% vs 3.9%, P < 0.05). The incidence varied almost zero to 40% due to the differences in the profiles of HBV antibodies. High anti-HBs (cut-off of 79.2 IU/L) or low anti-HBc levels (cut-off of 4.475, S/CO) at baseline were associated with a low risk of HBVr. Anti-HBe status did not affect the incidence of HBVr. However, the cut-offs were only predictive of HBVr in the patients who had negative anti-HBe.

CONCLUSION

The baseline profiles of HBV antibodies are predictive of the risk of HBVr in leukemia patients undergoing immunosuppression. However, seronegative anti-HBe is a prerequisite for using baseline anti-HBs and anti-HBc quantification to predict HBVr risk.

Insights for clinical diagnostic indicators of virus and host in chronic hepatitis B infection

Covalently closed circular DNA (cccDNA), which is stably present in the nucleus of hepatocytes, is an important indicator for evaluating antiviral efficacy. Since cccDNA quantification requires an invasive procedure, serum biological markers that can effectively reflect the transcriptional activity of intrahepatic virus and the efficacy of treatment are required. Here, from the aspects of virus and host, we outline the focus of clinical research of HBV in recent years, including HBV RNA, empty virus, hepatitis B core-related antigen and changes in the immune response. We briefly discuss their significance in predicting disease activity and monitoring treatment response in chronic hepatitis B. On this basis, some issues worthy of attention in laboratory diagnosis are proposed.

HBV Reactivation in Patients Undergoing Hematopoietic Stem Cell Transplantation: A Narrative Review

HBV reactivation (HBVr) can occur due to the ability of HBV to remain latent in the liver as covalently closed circular DNA and by the capacity of HBV to alter the immune system of the infected individuals. HBVr can occur in patients undergoing hematopoietic stem cell transplantation (HSCT) with a clinical spectrum that ranges from asymptomatic infection to fulminant hepatic failure. The risk of HBVr is determined by a complex interplay between host immunity, virus factors, and immunosuppression related to HSCT. All individuals who undergo HSCT should be screened for HBV. HSCT patients positive for HBsAg and also those HBcAb-positive/HBsAg-negative are at high risk of HBV reactivation (HBVr) due to profound and prolonged immunosuppression. Antiviral prophylaxis prevents HBVr, decreases HBVr-related morbidity and mortality in patients with chronic or previous HBV. The optimal duration of antiviral prophylaxis remains to be elucidated. The vaccination of HBV-naïve recipients and their donors against HBV prior to HSCT has an important role in the prevention of acquired HBV infection. This narrative review provides a comprehensive update on the current concepts, risk factors, molecular mechanisms, prevention, and management of HBVr in HSCT.

The role of hepatitis B core-related antigen in predicting hepatitis B virus recurrence after liver transplantation

BACKGROUND

Hepatitis B core-related antigen (HBcrAg) is a viral marker for the development of cirrhosis and hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). However, the relationship between HBcrAg and HBV recurrence after liver transplantation (LT) is unclear.

AIM

To investigate the correlation of serum HBcrAg level with HBV recurrence post-LT to evaluate the prognostic role of the pre-LT HBcrAg level.

METHODS

This retrospective cohort study enrolled 357 CHB patients who received LT for a median of 36.6 months. Univariate and multivariate analyses and time-dependent receiver operating characteristic (ROC) curves for markers associated with HBV recurrence were analysed.

RESULTS

48 patients (13.4%) had HBV recurrence after LT. HBcrAg, detectable HBV DNA, HCC and HCC recurrence were associated with HBV recurrence. In a multivariate analysis, HBcrAg level was independently associated with HBV recurrence, and the relationship between HBcrAg level and incident HBV recurrence was significant and graded (HR: 3.17 per unit; 95% CI: 1.97-5.11; P for trend < .001). Additionally, HBcrAg level was superior to HBV DNA level in predicting HBV recurrence by time-dependent ROC analysis. Patients with an HBcrAg ≥ 5.0 log U/mL had a significantly higher 5-year cumulative recurrence rate than those with an HBcrAg < 5.0 log U/mL (37.6% vs 6%, P < .001); the adjusted hazard ratio was 5.27 (95% CI 2.47-11.25, P < .001).

CONCLUSION

An elevated serum HBcrAg level was independently associated with the risk of HBV recurrence in patients with CHB after LT.

Roadmap to functional cure of chronic hepatitis B: An expert consensus

Hepatitis B virus (HBV) infection continues to be a major public health issue worldwide. HBsAg loss is associated with functional remission and improved long-term outcome, and is considered to be a 'functional cure' (also referred to as clinical or immunologic cure) for chronic hepatitis B. This ideal goal of therapy can be achieved using optimized combination regimens with direct-acting antivirals [eg nucleos(t)ide analogues (NAs)] and immunomodulators [eg pegylated interferon alpha2a (Peg-IFN)] in selected patients with chronic hepatitis B. Among different combination therapies currently available, those with NA lead-in followed by Peg-IFN in virally suppressed patients has been demonstrated to be effective. This review provides an updated overview of the evidence supporting the use of combination therapies and summarizes expert consensus on the roadmap to attain functional cure for chronic hepatitis B patients.

The Role of Hepatitis B Surface Antigen in Nucleos(t)ide Analogues Cessation Among Asian Patients With Chronic Hepatitis B: A Systematic Review

In actual clinical practice, infinite nucleos(t)ide analogues (NAs) treatment for chronic hepatitis B virus (HBV) infection is unrealistic. The most commonly used endpoint is suppression of HBV DNA to undetectable levels with normalization of alanine aminotransferase. However, this criterion for cessation of treatment is associated with various incidences of virological and clinical relapse. Recent studies suggest that decreasing the hepatitis B surface antigen (HBsAg) level at the end of treatment (EOT) to an appropriate cut-off value appears to be a practicable and attainable cessation criterion. We performed a systematic review to explore the optimal cut-off value of HBsAg at EOT for the cessation of NAs treatment. Eleven studies with 1,716 patients were included in this review. When the HBsAg levels at EOT were <100 IU/mL and >100 IU/mL, the respective off-therapy virological relapse rates were 9.1%-19.6% (range) and 31.4%-86.8% (range) at ≥12 months off therapy, regardless of hepatitis B e antigen (HBeAg) status; the respective off-therapy clinical relapse rates were 15.4%-29.4% (range) and 48.1%-63.6% (range) at ≥12 months off therapy, regardless of HBeAg status; and the respective off-therapy HBsAg loss rates were 21.1%-58.8% (range) and 3.3%-7.4% (range) for HBeAg-negative patients at ≥39 months off therapy. Conclusion: Cessation of long-term NAs therapy before HBsAg seroclearance in patients with chronic hepatitis B is a feasible alternative to indefinite treatment. An HBsAg level <100 IU/mL at EOT seems to be a useful marker for deciding when to discontinue NAs therapy. However, regular monitoring is required after the cessation of NAs treatment, and long-term outcomes must be further evaluated.

Elevated expression of serum soluble ST2 in clinical relapse after stopping long-term Nucleos(t)ide analogue therapy for chronic hepatitis B

Background

The virological or clinical relapse is common in chronic hepatitis B (CHB) patients after stopping long-term nucleos(t)ide analogue (NA) therapy. Soluble growth stimulation expressed gene 2 (sST2), one of the Toll-like/interleukin-1 receptor members, is involved in a variety of inflammatory processes and immune responses. However, the expression and function of serum sST2 in CHB patients after stopping NA treatment remains unknown.

Methods

A total of 91 non-cirrhotic Asian patients with CHB who discontinued NA therapy according to international guidelines were prospectively followed up to 240 weeks. All patients were divided into clinical relapse group and non-clinical relapse (including sustained virological response and only virological relapse) group according HBV DNA and ALT levels. The serum levels of sST2 of all participants were determined by ELISA and compared between each two groups.

Results

Clinical relapse occurred in 26 patients and virological relapse occurred in 57 patients. We found that there was a positive correlation between sST2 expression and HBsAg, ALT, HBV DNA, and anti-HBc levels in CHB patients after discontinuation of NA treatment. Levels of serum sST2 in clinical relapse patients showed a rising trend and most patients showed peak sST2 levels at the point of clinical relapse. Moreover, the sST2 levels of clinical relapse group at week 12, week 24 and week 48 were relatively higher than non-clinical relapse group. However, the level of sST2 at the end of treatment was not an effective biological marker for the early prediction of clinical relapse after discontinuation of long-term NA therapy.

Conclusions

In conclusion, we found that an increase in sST2 in clinical relapse patients might be associated with an inflammation-related immune response after discontinuation of NA treatment.

Trial registration

The trial was retrospectively registered at Chinese Clinical Trial Registry: ChiCTR-OOC-17013970. Registration date: December 15, 2017.

Cellular DNA Topoisomerases Are Required for the Synthesis of Hepatitis B Virus Covalently Closed Circular DNA

In order to identify host cellular DNA metabolic enzymes that are involved in the biosynthesis of hepatitis B virus (HBV) covalently closed circular (ccc) DNA, we developed a cell-based assay supporting synchronized and rapid cccDNA synthesis from intracellular progeny nucleocapsid DNA. This was achieved by arresting HBV DNA replication in HepAD38 cells with phosphonoformic acid (PFA), a reversible HBV DNA polymerase inhibitor, at the stage of single-stranded DNA and was followed by removal of PFA to allow the synchronized synthesis of relaxed circular DNA (rcDNA) and subsequent conversion into cccDNA within 12 to 24 h. This cccDNA formation assay allows systematic screening of the effects of small molecular inhibitors of DNA metabolic enzymes on cccDNA synthesis but avoids cytotoxic effects upon long-term treatment. Using this assay, we found that all the tested topoisomerase I and II (TOP1 and TOP2, respectively) poisons as well as topoisomerase II DNA binding and ATPase inhibitors significantly reduced the levels of cccDNA. It was further demonstrated that these inhibitors also disrupted cccDNA synthesis during de novo HBV infection of HepG2 cells expressing sodium taurocholate cotransporting polypeptide (NTCP). Mechanistic analyses indicate that whereas TOP1 inhibitor treatment prevented the production of covalently closed negative-strand rcDNA, TOP2 inhibitors reduced the production of this cccDNA synthesis intermediate to a lesser extent. Moreover, small interfering RNA (siRNA) knockdown of topoisomerase II significantly reduced cccDNA amplification. Taking these observations together, our study demonstrates that topoisomerase I and II may catalyze distinct steps of HBV cccDNA synthesis and that pharmacologic targeting of these cellular enzymes may facilitate the cure of chronic hepatitis B.IMPORTANCE Persistent HBV infection relies on stable maintenance and proper functioning of a nuclear episomal form of the viral genome called cccDNA, the most stable HBV replication intermediate. One of the major reasons for the failure of currently available antiviral therapeutics to cure chronic HBV infection is their inability to eradicate or inactivate cccDNA. We report here a chemical genetics approach to identify host cellular factors essential for the biosynthesis and maintenance of cccDNA and reveal that cellular DNA topoisomerases are required for both de novo synthesis and intracellular amplification of cccDNA. This approach is suitable for systematic screening of compounds targeting cellular DNA metabolic enzymes and chromatin remodelers for their ability to disrupt cccDNA biosynthesis and function. Identification of key host factors required for cccDNA metabolism and function will reveal molecular targets for developing curative therapeutics of chronic HBV infection.

Serum HBcrAg is better than HBV RNA and HBsAg in reflecting intrahepatic covalently closed circular DNA

The correlation between serum HBcrAg and HBV RNA is unclear, and correlations of intrahepatic cccDNA with HBcrAg, HBV RNA and HBsAg are rarely reported in the same cohort. This study aimed to assess the correlation of HBcrAg with HBV RNA and HBsAg, and investigate whether serum HBcrAg is superior to serum HBV RNA and HBsAg in reflecting intrahepatic HBV cccDNA in HBeAg-positive and HBeAg-negative CHB patients. In this study, 85 HBeAg-positive and 25 HBeAg-negative patients who have never received antiviral therapy were included. Among HBeAg-positive patients, HBcrAg was correlated positively with HBsAg (r = 0.564, P < 0.001) and HBV RNA (r = 0.445, P < 0.001), and HBV RNA was also correlated positively with HBsAg (r = 0.323, P = 0.003). Among HBeAg-negative patients, no significant correlation was observed between HBcrAg, HBsAg and HBV RNA. By multivariable linear regression, HBcrAg (β = -0.563, P < 0.001), HBsAg (β = -0.328, P < 0.001) and HBV RNA (β = 0.180, P = 0.003) were all associated with cccDNA levels among HBeAg-positive patients, but only serum HBcrAg was associated with cccDNA level (β = 0.774, P = 0.000) among HBeAg-negative patients. HBcrAg was better correlated with cccDNA as compared to HBsAg and HBV RNA, irrespective of HBeAg status. Among HBeAg-positive patients, though HBcrAg level was influenced by hepatic inflammatory activity and HBV DNA levels, the good correlations of HBcrAg with cccDNA persisted after stratification by inflammatory activity and HBV DNA levels. In conclusion, correlations of serum HBcrAg, HBV RNA and HBsAg levels differ significantly between HBeAg-positive and HBeAg-negative patients, but serum HbcrAg correlates with cccDNA levels better than HBV RNA and HBsAg, irrespective of HBeAg status.

Correlation of HBcrAg with Intrahepatic Hepatitis B Virus Total DNA and Covalently Closed Circular DNA in HBeAg-Positive Chronic Hepatitis B Patients

The purpose of this study was to explore the correlations of serum hepatitis B core-related antigen (HBcrAg) with intrahepatic Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) and HBV total DNA in hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) patients. Serum HBcrAg and other parameters, including HBV DNA, HBV RNA, HBeAg, hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were quantitatively measured at baseline and follow-up time points. Intrahepatic HBV cccDNA and total DNA were quantitatively detected at baseline and 96 weeks. Grading of liver necroinflammation and staging of hepatic fibrosis were assessed at baseline and 96 weeks. Correlations between serum HBcrAg and other parameters were analyzed by Pearson's correlation analysis. The results showed that pretreatment HBcrAg correlated significantly with HBV total DNA levels (r = 0.328, P  = 0.003) in 82 CHB patients, and, after removing three outliers, with intrahepatic HBV cccDNA (r = 0.323, P  = 0.004; n = 79). Serum HBcrAg correlated better with HBV cccDNA in patients with lower levels of serum HBV DNA (stratified by 7 log IU/ml of HBV DNA; r = 0.656, P  = 0.003 versus r = -0.02, P = 0.866). Significant inverse correlations were found between HBcrAg and grade of liver necroinflammation (r = -0.245, P  = 0.037), stage of hepatic fibrosis (r = -0.360, P  = 0.002) at baseline. Serum HBcrAg presented significant correlation with intrahepatic HBV cccDNA in patients with HBeAg seroconversion at 96 weeks (r = 0.622, P  = 0.006). The decrease in HBcrAg showed significant correlation with the decrease in HBV cccDNA after 96-week NA therapy (r = 0.282, P  = 0.043). Serum HBcrAg also correlated significantly with other serum markers at baseline and 96 weeks of NA therapy. In conclusion, baseline HBcrAg and its decreased value were significantly correlated with the corresponding intrahepatic HBV cccDNA.

Integration of hepatitis B virus S gene impacts on hepatitis B surface antigen levels in patients with antiviral therapy

BACKGROUND AND AIM

The aim of this study is to investigate the impact of hepatitis B virus (HBV) S gene integration on serum hepatitis B surface antigen (HBsAg) levels in chronic hepatitis B with long-term nucleos(t)ide analogue (NUC) therapy.

METHODS

Chronic hepatitis B patients who performed liver biopsy at baseline and treated with long-term NUC therapy were recruited. The integration of HBV S gene in baseline liver biopsy specimen was detected by Alu polymerase chain reaction method. Serum HBsAg levels were measured at baseline and the second year and the fourth year after NUC therapy by Roche reagent, respectively. Serum HBsAg levels between HBV S gene integrated group and nonintegrated group were compared and analyzed.

RESULTS

Seventy patients were eligible for this study. Among them, 11 (15.7%) were found to have HBV S gene integration in their baseline liver biopsy specimens. Similar significant decrease of HBsAg levels was found in both integrated and nonintegrated groups (2.63 vs 2.65 log IU/mL, P = 0.478) after the first 2 years of NUC therapy. Thereafter, the decrease of HBsAg level from 2 to 4 years after therapy was largely unchanged in integrated group as compared with that of nonintegrated group (0.1 vs 2.53 log IU/mL, P = 0.002), with statistical difference.

CONCLUSIONS

Serum HBsAg could be originated from the expression of the integrated HBV S gene in patients with S gene integration, which implicated the limitations when regarding HBsAg as a surrogate biomarker of covalently closed circular DNA activity and as an indicator of safe NUC discontinuation.

Letter: serum HBcrAg is a useful marker for disease monitoring, predicting treatment response and disease outcome of chronic hepatitis B virus infection

Linked content

This article is linked to Mak et al and Mak and Yuen papers. To view these articles visit https://doi.org/10.1111/apt.14376 and https://doi.org/10.1111/apt.14684.

Combinational use of hepatitis B viral antigens predicts responses to nucleos(t)ide analogue/peg-interferon sequential therapy

BACKGROUND

This prospective cohort study searched for factors associated with a response to nucleos(t)ide analogue/peg-interferon (NUC/peg-IFN) sequential therapy.

METHODS

A total of 95 patients with chronic hepatitis B being treated with NUCs were enrolled. Immediately following NUC cessation, peg-IFN was administered at 180 µg/dose weekly for 48 weeks.

RESULTS

Twenty-six patients (27%) were judged to be responders at 48 weeks after the completion of peg-IFN. Analysis of baseline factors revealed that hepatitis B surface antigen (HBsAg) <3.1 log IU/ml and HB core-related antigen (HBcrAg) <3.9 log U/ml were significant indicators of a treatment response. The levels of the markers decreased in both responders and non-responders during peg-IFN therapy but continued falling in responders only after halting peg-IFN. Lower HBsAg (<2.0 log IU/ml) and HBcrAg (<3.8 log U/ml) levels at the time of response judgment were also significantly associated with a favorable response. While lower HBcrAg at baseline was the sole predictor of decreased HBcrAg levels at judgment, lower HBsAg, lower HBcrAg, and the use of adefovir dipivoxil at baseline predicted decreased HBsAg levels at the study endpoint. The use of adefovir dipivoxil was also associated with higher serum IFN-λ3, which might have contributed to the reduction in patient HBsAg levels.

CONCLUSIONS

The combinational use of HBsAg and HBcrAg levels at baseline and their changes throughout sequential therapy may be useful for predicting a response to NUC/peg-IFN sequential therapy.

Analysis of intrahepatic total HBV DNA, cccDNA and serum HBsAg level in Chronic Hepatitis B patients with undetectable serum HBV DNA during oral antiviral therapy

BACKGROUND

This study aimed to investigate the relationship between intrahepatic cccDNA and serum HBsAg in chronic Hepatitis B (CHB) patients with undetectable serum HBV DNA during antiviral therapy.

METHODS

We investigated HBsAg serum levels and their relationship to intrahepatic total cccDNA and HBV DNA in CHB patients with undetectable serum HBV DNA during oral antiviral therapy. Intrahepatic cccDNA and HBV DNA quantitation were performed in the same needle biopsy material, while serum HBsAg, HBeAg and HBV DNA levels were measured in samples drawn on the day of the liver biopsy.

RESULTS

A total of 90 patients who had a liver biopsy were enrolled, including 80 patients with CHB and 10 patients with liver cirrhosis (LC). All the CHB patients were divided into HBeAg-positive and HBeAg-negative group. By using real-time PCR detection, we found that intrahepatic cccDNA and HBV DNA levels were higher in CHB patients than those in LC patients (Intrahepatic cccDNA: 6.15±1.19 vs. 6.12±0.36, HBV DNA: 7.26±0.49 vs. 5.59±0.45, both P<0.05). Intrahepatic cccDNA level was positively correlated with serum HBsAg in HBeAg-negative (r=0.66, P=0.02) and lower serum HBeAg (≤50S/CO) CHB patients (r=0.47, P=0.03), but not in higher serum HBeAg (>50S/CO) CHB patients (both P>0.05). In HBeAg negative patients, serum HBsAg level was correlated with intrahepatic total HBV DNA level (r=0.52, P=0.006). However, no relationship between HBsAg level and intrahepatic total HBV DNA level was found in HBeAg positive patients (both P>0.05).

CONCLUSIONS

Serum HBsAg can be used to predict intrahepatic cccDNA and HBV DNA level in CHB patients with low serum HBeAg statues, especially in HBeAg negative patients.

Epigenetic regulation of hepatitis B virus covalently closed circular DNA: Implications for epigenetic therapy against chronic hepatitis B

Hepatitis B virus (HBV) infection represents a significant public health burden worldwide. Although current therapeutics manage to control the disease progression, lifelong treatment and surveillance are required because drug resistance develops during treatment and reactivations frequently occur following medication cessation. Thus, the occurrence of hepatocellular carcinoma is decreased, but not eliminated. One major reason for failure of HBV treatment is the inability to eradicate or inactivate the viral covalently closed circular DNA (cccDNA), which is a stable episomal form of the viral genome decorated with host histones and nonhistone proteins. Accumulating evidence suggests that epigenetic modifications of cccDNA contribute to viral replication and the outcome of chronic HBV infection. Here, we summarize current progress on HBV epigenetics research and the therapeutic implications for chronic HBV infection by learning from the epigenetic therapies for cancer and other viral diseases, which may open a new venue to cure chronic hepatitis B. (Hepatology 2017;66:2066-2077).

Mechanism of Hepatitis B Virus Persistence in Hepatocytes and Its Carcinogenic Potential

Liver disease associated with persistent infection with hepatitis B virus (HBV) continues to be a major health problem of global impact. Despite the existence of an effective vaccine, at least 240 million people are chronically infected worldwide, and are at risk of developing liver cirrhosis and hepatocellular carcinoma. Although chronic HBV infection is considered the main risk factor for liver cancer development, the molecular mechanisms determining persistence of infection and long-term pathogenesis are not fully elucidated but appear to be multifactorial. Current therapeutic regimens based on the use of polymerase inhibitors can efficiently suppress viral replication but are unable to eradicate the infection. This is due both to the persistence of the HBV genome, which forms a stable minichromosome, the covalently closed circular DNA (cccDNA), in the nucleus of infected hepatocytes, as well as to the inability of the immune system to efficiently counteract chronic HBV infection. In this regard, the unique replication strategies adopted by HBV and viral protein production also appear to contribute to infection persistence by limiting the effectiveness of innate responses. The availability of improved experimental systems and molecular techniques have started to provide new information about the complex network of interactions that HBV establishes within the hepatocyte and that may contribute to disease progression and tumor development. Thus, this review will mostly focus on events involving the hepatocyte: the only target cell where HBV infection and replication take place.

Synthesis of sulfamoylbenzamide derivatives as HBV capsid assembly effector

The synthesis of novel series of sulfamoylbenzamides as HBV capsid assembly effector is reported. The structure was divided into five parts which were independently modified as part of our lead optimization. All synthesized compounds were evaluated for their anti-HBV activity and toxicity in human hepatocytes, lymphocytes and other cells. Additionally, we assessed their effect on HBV cccDNA formation in an HBeAg reporter cell-based assay. Among the 27 compounds reported, several analogs exhibited submicromolar activities and significant reduction of HBeAg secretion. Selected compounds were studied under negative-stain electron microscopy for their ability to disrupt the HBV capsid formation. Structures were modeled into a binding site recently identified in the HBV capsid protein for similar molecules to rationalize the structure-activity relationships for this family of compounds.

Serum Hepatitis B Virus DNA, RNA, and HBsAg: Which Correlated Better with Intrahepatic Covalently Closed Circular DNA before and after Nucleos(t)ide Analogue Treatment?

The study was designed to investigate whether serum hepatitis B virus (HBV) RNA is a strong surrogate marker for intrahepatic HBV covalently closed circular DNA (cccDNA) compared with serum HBV DNA, hepatitis B surface antigen (HBsAg), and hepatitis B e antigen (HBeAg) in HBeAg-positive chronic hepatitis B (CHB) patients. Serum HBV RNA, HBV DNA, HBsAg, HBeAg, and intrahepatic cccDNA were quantitatively detected at baseline (n = 82) and 96 weeks (n = 62) after treatment with nucleos(t)ide analogue (NUC) in HBeAg-positive CHB patients. The correlations among serum HBV RNA, HBV DNA, HBsAg, HBeAg, and intrahepatic cccDNA levels were then statistically analyzed. The results showed that pretreatment intrahepatic cccDNA levels correlated better with serum HBV DNA levels (r = 0.36, P < 0.01) than with serum HBV RNA levels (r = 0.25, P = 0.02), whereas no correlations were found between pretreatment intrahepatic cccDNA levels and HBsAg (r = 0.15, P = 0.17) or HBeAg (r = 0.07, P = 0.56) levels. At 96 weeks after NUC treatment, intrahepatic cccDNA levels correlated well with HBsAg levels (r = 0.39, P < 0.01) but not with serum HBV RNA, HBV DNA, and HBeAg levels (all P > 0.05). Besides, the decline in the intrahepatic cccDNA level from baseline to week 96 correlated better with the reduction in the serum HBsAg levels than with the decreases in the levels of the other markers (for the HBsAg decline, r = 0.38, P < 0.01; for the HBV DNA decline, r = 0.35, P = 0.01; for the HBV RNA decline, r = 0.28, P < 0.05; for the HBeAg decline, r = 0.18, P = 0.19). In conclusion, the baseline serum HBV RNA level or its decline after 96 weeks of NUC therapy correlated with the corresponding intrahepatic cccDNA level, while it was less than that seen with serum HBV DNA at baseline and HBsAg (or its decline) at 96 weeks after treatment, respectively.

Baseline value of intrahepatic HBV DNA over cccDNA predicts patient's response to interferon therapy

Methodology for accurate quantification of intra-hepatic cccDNA has long been a technical challenge, yet it is highly desired in the clinic. Here, we developed a sensitive method for quantification of intrahepatic cccDNA in liver biopsies from patients, which allowed to predict patient’s response to interferon therapy at baseline. Twenty-five patients with HBeAg+ CHB were recruited and liver biopsies were obtained at baseline and 1-year after interferon treatment, respectively. Both intrahepatic cccDNA and HBV DNA were absolutely quantified by a droplet digital PCR amplification system. Patients were categorized as either responder or non-responder group based on their HBeAg status 1-year after interferon therapy. Levels of both intrahepatic HBV DNA and HBV cccDNA were significantly reduced after interferon treatment among the responders, but not the non-responders, in comparison with their levels at baseline. Baseline values of intrahepatic HBV DNA over cccDNA significantly correlated with patient’s response to PEG-IFN therapy (P = 0.000). In addition, HBeAg seroconversion also correlates with a significant reduction in intrahepatic pgRNA production among the responders after interferon therapy (P = 0.030). In conclusion, our results suggest that baseline value of intrahepatic HBV DNA over cccDNA may be a preferable indicator for selecting appropriate patients for IFN-based therapy in the clinic.

The Role of cccDNA in HBV Maintenance

Chronic hepatitis B virus (HBV) infection continues to be a major health burden worldwide; it can cause various degrees of liver damage and is strongly associated with the development of liver cirrhosis and hepatocellular carcinoma. The molecular mechanisms determining HBV persistence are not fully understood, but these appear to be multifactorial and the unique replication strategy employed by HBV enables its maintenance in infected hepatocytes. Both the stability of the HBV genome, which forms a stable minichromosome, the covalently closed circular DNA (cccDNA) in the hepatocyte nucleus, and the inability of the immune system to resolve chronic HBV infection are believed to be key mechanisms of HBV chronicity. Since a true cure of HBV requires clearance of intranuclear cccDNA from infected hepatocytes, understanding the mechanisms involved in cccDNA biogenesis, regulation and stability is mandatory to achieve HBV eradication. This review will summarize the state of knowledge on these mechanisms including the impact of current treatments on the cccDNA stability and activity. We will focus on events challenging cccDNA persistence in dividing hepatocytes.

Detection of HBV Covalently Closed Circular DNA

Chronic hepatitis B virus (HBV) infection affects approximately 240 million people worldwide and remains a serious public health concern because its complete cure is impossible with current treatments. Covalently closed circular DNA (cccDNA) in the nucleus of infected cells cannot be eliminated by present therapeutics and may result in persistence and relapse. Drug development targeting cccDNA formation and maintenance is hindered by the lack of efficient cccDNA models and reliable cccDNA detection methods. Southern blotting is regarded as the gold standard for quantitative cccDNA detection, but it is complicated and not suitable for high-throughput drug screening, so more sensitive and simple methods, including polymerase chain reaction (PCR)-based methods, Invader assays, in situ hybridization and surrogates, have been developed for cccDNA detection. However, most methods are not reliable enough, and there are no unified standards for these approaches. This review will summarize available methods for cccDNA detection. It is hoped that more robust methods for cccDNA monitoring will be developed and that standard operation procedures for routine cccDNA detection in scientific research and clinical monitoring will be established.

Hepatitis B Reactivation Associated With Immune Suppressive and Biological Modifier Therapies: Current Concepts, Management Strategies, and Future Directions

Hepatitis B reactivation associated with immune-suppressive and biological therapies is emerging to be an important cause of morbidity and mortality in patients with current or prior exposure to hepatitis B virus (HBV) infection. The population at risk for HBV reactivation includes those who either currently are infected with HBV or have had past exposure to HBV. Because curative and eradicative therapy for HBV is not currently available, there is a large reservoir of individuals at risk for HBV reactivation in the general population. HBV reactivation with its potential consequences is particularly a concern when these people are exposed to either cancer chemotherapy, immunosuppressive or biologic therapies for the management of rheumatologic conditions, malignancies, inflammatory bowel disease, dermatologic conditions, or solid-organ or bone marrow transplantation. With the advent of newer and emerging forms of targeted biologic therapies, it has become important to understand the mechanisms whereby certain therapies are more prone to HBV reactivation. This review provides a comprehensive update on the current concepts, risk factors, molecular mechanisms, prevention, and management of hepatitis B reactivation. In addition, we provide recommendations for future research in this area.

The relationship between HBcrAg and HBV reinfection in HBV related post-liver transplantation patients

BACKGROUND

Post-transplant hepatitis B virus (HBV) reinfection is one of the major problems facing patients who undergo HBV-related liver transplantation (LT). We analyzed the clinical impact of serum hepatitis B core-related antigen (HBcrAg) on HBV reinfection in post-LT patients with HBV-related liver diseases.

METHODS

Serum hepatitis B surface antigen (HBsAg), HBV DNA, and HBcrAg were measured over time in 32 post-LT patients. Twenty-one out of 32 patients had HCC at LT. The effects of HBcrAg, hepatocellular carcinoma (HCC) recurrence, and HBs gene mutation on HBV reinfection and withdrawal from hepatitis B immune globulin (HBIG) were analyzed.

RESULTS

Sixteen out of 32 patients (50 %) were positive for HBcrAg even though only six patients were thought to have experienced HBV reinfection based on reappearance of either HBV DNA or HBsAg during a median follow-up time of 75 months. Three of these six patients who became re-infected with HBV experienced HCC recurrence after LT. The HBV DNA reappearance rate was significantly higher in patients with HCC recurrence after LT (p < 0.001). Two HBV re-infected patients without HCC recurrence had HBs gene mutations G145R and G145A, respectively. Anti-HBs antibody development rate by HB vaccination was similar between HBcrAg-positive and negative patients (p = 0.325).

CONCLUSIONS

HBV reinfection is more common than is usually considered based on conventional measurement of HBsAg and HBV DNA. HCC recurrence and mutations in the HBV S gene were associated with HBV reinfection after LT.

Kinetics of serum HBsAg and intrahepatic cccDNA during pegylated interferon therapy in patients with HBeAg-positive and HBeAg-negative chronic hepatitis B

This study was aimed at comparing clinical applicability of serum HBsAg quantification in relation to intrahepatic covalently closed-circular DNA (cccDNA) in patients with HBeAg-positive and HBeAg-negative chronic hepatitis B (CHB) treated with pegylated interferon (PEG-IFN) monotherapy for 48 weeks. Overall, 32 and 36 patients with HBeAg-positive and HBeAg-negative CHB, respectively were recruited. Paired liver biopsies at baseline and end of therapy were analyzed for cccDNA. Virological response (VR) at 48 weeks post-treatment was defined as HBeAg clearance (for HBeAg-positive CHB) and HBV DNA <2,000 IU/ml (for both groups). The results demonstrated that baseline levels of all viral markers were higher in the HBeAg-positive group than the HBeAg-negative group. Baseline HBsAg correlated with cccDNA in the HBeAg-positive group (r = 0.452, P = 0.009) but not in the HBeAg-negative group (r = 0.018, P = 0.919). However, the magnitude of cccDNA and HBsAg decline at end of treatment was not different between groups. The reduction of HBsAg showed a positive correlation with cccDNA decline in HBeAg-positive and HBeAg-negative CHB (r = 0.544, P = 0.001 and r = 0.364, P = 0.029, respectively). Overall, responders had more decline in cccDNA and HBsAg levels compared with non-responders. Patients with serum HBsAg decline of >1.0 log10  IU/ml during treatment archived VR and HBsAg clearance of 80% and 30%, respectively. In conclusion, serum HBsAg represented a better surrogate marker of intrahepatic cccDNA in patients with HBeAg-positive CHB compared to those with HBeAg-negative CHB. On-treatment, HBsAg reduction of 1.0 log10  IU/mL was associated with a high probability of subsequent VR and HBsAg clearance in patients receiving PEG-IFN therapy. J. Med. Virol. 89:130-138, 2017. © 2016 Wiley Periodicals, Inc.

Treatment of hepatitis B virus: an update

Chronic hepatitis B virus infection is a global health concern as it affects over 240 million people worldwide and an estimated 686,000 people die annually as a result of complications of the disease. With the development of newer antiviral drugs, viral suppression of HBV is achievable, however elimination of HBV from infected individuals (functional cure) remains an issue. Due to persistence of HBV DNA (cccDNA) in infected cells, chronically infected patients who discontinue therapy prior to HBsAg loss or seroconversion are likely to relapse. Several novel therapeutic strategies are being researched and studied in clinical trials. Here we review these novel strategies to achieve sustained cure or elimination of HBV. These strategies include the targeting of the host or viral factors required for viral persistence as well as therapeutic vaccines.

The current status and future directions of hepatitis B antiviral drug discovery

INTRODUCTION

The current standard care of chronic hepatitis B fails to induce a durable off-drug control of hepatitis B virus (HBV) replication in the majority of treated patients. The primary reasons are its inability to eliminate the covalently closed circular (ccc) DNA, the nuclear form of HBV genome, and restoration of the dysfunctional host antiviral immune response against the virus. Accordingly, discovery and development of therapeutics to completely stop HBV replication, eliminate or functionally inactivate cccDNA as well as activate a functional antiviral immune response against HBV are the primary efforts for finding a cure for chronic hepatitis B. Area covered: Herein, the authors highlight the current efforts of HBV drug discovery and offer their opinions for the future directions of this research. Expert opinion: The authors believe that through a consecutive or overlapping three-stage antiviral and immunotherapy program to: (i) completely stop HBV replication and cccDNA amplification; (ii) reduce viral antigen load and induce HBV surface antigen (HBsAg) seroclearance through eradication or inactivation of cccDNA and RNA interference-mediated degradation of viral mRNA and (iii) activate a functional antiviral immune response against HBV through therapeutic immunization or immunotherapy, a functional cure of chronic HBV infection can be achieved in the majority of chronic HBV carriers.

Aiming for cure in HBV and HDV infection

Chronic hepatitis B virus (HBV) infection continues to be a major health burden worldwide. Currently available antiviral treatment options for chronic hepatitis B include pegylated interferon alpha2a (PegIFN) or nucleos(t)ide analogues (NAs). The major advantages of NAs are good tolerance and potent antiviral activity associated with high rates of sustained on-treatment response to therapy. The advantages of PegIFN include a finite course of treatment, the absence of drug resistance, and an opportunity to obtain a durable post-treatment response to therapy. Furthermore, PegIFN is the only approved agent known to be active against hepatitis D virus (HDV). The use of these two antiviral agents with different mechanisms of action in combination against hepatitis B is theoretically an attractive approach for treatment. Although several studies have confirmed certain virological advantages of combination therapies, data supporting a long-term clinical benefit for patients are lacking and monotherapy with PegIFN or NAs remains the therapy of choice. Moreover, with the current treatment approaches, only a limited number of patients achieve hepatitis B surface antigen (HBsAg) loss. HBsAg loss is considered a "functional cure", but does not mean viral eradication. There is a need for novel therapeutic approaches that enable not only suppression of viral replication, but resolution of HBV infection. A key challenge is to target covalently closed circular DNA (cccDNA) in the nucleus of infected hepatocytes. The recent development and availability of innovative in vitro and in vivo systems and sensitive molecular techniques has opened new possibilities to study the complex network of interactions that HBV establishes with the host in the course of infection and to define new targets for antiviral strategies. Several new antiviral or immunomodulatory compounds have reached preclinical or clinical testing with the aim of silencing or eradicating cccDNA to achieve functional cure. Many of these strategies may also be effective for the treatment of HDV, which is dependent on HBsAg for its life cycle. This Clinical Trial Watch summarizes the most recent therapeutic strategies designed to directly target the viruses B and D or to improve immune responses during chronic HBV infection.

Decay of ccc-DNA marks persistence of intrahepatic viral DNA synthesis under tenofovir in HIV-HBV co-infected patients

BACKGROUND & AIMS

In the presence of highly-potent antivirals, persistence of hepatitis B virus (HBV) is most well-characterized by covalently-closed circular DNA (cccDNA) and total intrahepatic DNA (IH-DNA). We sought to determine how antiviral therapy could affect their levels during human immunodeficiency virus (HIV)-HBV co-infection.

METHODS

Sixty co-infected patients from a well-defined cohort with ⩾1 liver biopsy were studied. HBV cccDNA and total IH-DNA were extracted from biopsies and quantified by real-time PCR. Factors associated with intrahepatic viral load were determined using mixed-effect linear regression and half-life viral kinetics during reconstructed follow-up using non-linear exponential decay models.

RESULTS

At biopsy, 35 (58.3%) patients were hepatitis B "e" antigen (HBeAg)-positive and 33 (55.0%) had detectable plasma HBV-DNA (median=4.58log10IU/ml, IQR=2.95-7.43). Overall, median cccDNA was -0.95log10copies/cell (IQR=-1.70, -0.17) and total IH-DNA was 0.27log10copies/cell (IQR=-0.39, 2.00). In multivariable analysis, significantly lower levels of cccDNA and total IH-DNA were observed in patients with HBeAg-negative serology, nadir CD4(+) cell counts >250/mm(3), and longer cumulative TDF-duration, but not lamivudine- or adefovir-duration. In post-hoc analysis using reconstructed TDF-duration (median 29.6months, IQR=15.0-36.1, n=31), average half-life of cccDNA was estimated at 9.2months (HBeAg-positive=8.6, HBeAg-negative=26.2) and total IH DNA at 5.8months (HBeAg-positive=1.3, HBeAg-negative=13.6). Intrahepatic viral loads remained detectable for all patients, even with prolonged TDF-exposure.

CONCLUSIONS

In co-infection, TDF-use is associated with lower levels of HBV replication intermediates and cccDNA. Slow decay of intrahepatic viral loads underscores that TDF is unable to completely block intracellular viral DNA synthesis, which possibly accounts for continuous replenishment of the cccDNA pool.

LAY SUMMARY

Chronic hepatitis B virus (HBV) is a persistent infection, while the only real way of knowing the extent of this persistence is through measuring levels of virus in the liver. In this study, we examine levels of HBV in the liver among patients with both HBV and human immunodeficiency virus, or HIV, infection. It would appear that the currently available medication, namely "tenofovir", works well to decrease virus levels in the liver, but it remains at low levels despite long periods of treatment.

Serum HBV core-related antigen is a good predictor for spontaneous HBeAg seroconversion in chronic hepatitis B patients

Early prediction of spontaneous hepatitis B virus e antigen (HBeAg) seroconversion is pivotal in the prevention of unnecessary drug prescription, corresponding financial burden, and adverse reactions. One hundred and thirteen chronic hepatitis B patients with HBeAg-positive in the immune active phase were followed up for about 1.5 years. Patients were classified into two groups: spontaneous HBeAg seroconversion group (group A, n = 18) and non-spontaneous HBeAg seroconversion group. Among the non-spontaneous HBeAg seroconversion group, 35 patients were selected as controls (group B, n = 35). At week 12, there was a significant difference in hepatitis B core-related antigen (HBcrAg) levels between the two groups (group A 4.32 ± 1.05 log₁₀  kU/ml, and group B 5.16 ± 0.53 log₁₀  kU/ml, P = 0.004), and this significance magnified at week 28. Only two variables, HBcrAg level and the reduction in the HBcrAg levels (ΔHBcrAg) at week 28 were enrolled, with the odds ratio of 4.19 and 0.21, respectively. The optimal cutoffs of HBcrAg levels and the ΔHBcrAg at week 28 were 4.90 and 2.00 log₁₀  kU/ml, respectively. The positive predictive value and negative predictive value of HBcrAg levels at week 28 were 73.9% and 96.7%, respectively. The positive predictive value and negative predictive value of the ΔHBcrAg at week 28 were 76.2% and 93.8%, respectively. The measurement of HBcrAg is useful for monitoring the natural course of chronic hepatitis B virus infection. The dynamics of HBcrAg levels could accurately predict the spontaneous HBeAg seroconversion. J. Med. Virol. 89:463-468, 2017. © 2016 Wiley Periodicals, Inc.

Serum hepatitis B core-related antigen as a treatment predictor of pegylated interferon in patients with HBeAg-positive chronic hepatitis B

BACKGROUND & AIMS

The role of quantitative serum hepatitis B core-related antigen (HBcrAg) in patients with chronic hepatitis B (CHB) receiving pegylated interferon (PEG-IFN) is unclear. This study was aimed at comparing its usefulness with quantitative HBsAg in patients with HBeAg-positive CHB receiving PEG-IFN therapy.

METHODS

A total 46 patients treated with PEG-IFN for 48 weeks were retrospectively analysed. Intrahepatic covalently closed circular DNA (cccDNA) from paired liver biopsies and serial serum HBsAg and HBcrAg during therapy were assessed.

RESULTS

Virological response (VR), defined as HBeAg clearance and HBV DNA <2000 IU/ml at 24 weeks post treatment, was achieved in 15 (32.6%) patients. Responders had significantly higher cccDNA decline from baseline compared with non-responders. Baseline HBsAg and HBcrAg were correlated with cccDNA (r = 0.424, P = 0.020 and r = 0.564, P = 0.001, respectively), and changes in the corresponding markers during therapy were correlated with cccDNA reduction (r = 0.579, P = 0.001 and r = 0.503, P = 0.005, respectively). Responders showed more rapid decline of both markers during therapy compared with non-responders. In multivariate analysis, serum HBcrAg at week 12 was identified as a predictor of VR. The optimal cut-off value for HBcrAg (log10 8.0 U/ml) provided negative predictive value (NPV) of achieving VR at weeks 12 and 24 of 94.4 and 100%, respectively, while using HBsAg > 20 000 IU/ml provided NPV of 80 and 100% respectively.

CONCLUSIONS

The convenient quantitative HBcrAg represented a reliable marker of intrahepatic cccDNA. Monitoring HBcrAg levels during PEG-IFN therapy may help identify patients with a very low probability of response comparable to, if not better than, quantitative HBsAg.

Hepatitis B viral infection of hepatic progenitor cells. Resolving unresolved questions?

Accumulated data to date do not entirely explain the; propensity of the hepatitis B virus (HBV) to cause chronic infections in newborns; failure of antiviral agents to resolve infections or precise mechanism whereby HBV causes hepatocellular carcinoma (HCC). Based on the increased numbers of hepatic stem/progenitor cells (HPCs) present within the neonatal liver, the refractoriness of these cells to the effects of interferons and xenobiotics and their ability to undergo malignant transformation, we hypothesize that HBV infection of HPCs could explain these and perhaps other clinical features of chronic HBV.

CRISPR/Cas9 produces anti-hepatitis B virus effect in hepatoma cells and transgenic mouse

Chronic infection of hepatitis B virus (HBV) is at risk of liver cirrhosis and hepatocellular carcinoma and remains one of the major public health problems worldwide. It is a major barrier of persistence HBV cccDNA under current antiviral therapy as novel strategies of disrupting HBV cccDNA is pressing. The (CRISPR)/Cas9 system is presently emerging in gene editing and we also apply it for targeting and deleting the conserved regions of HBV genome. Two homologous sequences of HBV S and X genes were carried with CRISPR/Cas9 endonuclease to build pCas9 constructs, which may mediate anti-HBV effects of in vitro and in vivo systems in this study. The results showed the better anti-HBV productions by pCas9-2 and without significant differences in between Huh7 and HepG2 cells. CRISPR/Cas9 direct cleavage and mutagenesis were further analyzed of in vitro system. In the M-TgHBV mouse model of HBV, injection of pCas9 constructs by hydrodynamics decreased HBsAg of sera and liver HBcAg. In conclusion, this designed CRISPR/Cas9 system can induce anti-HBV effects and potentially consider as a novel therapeutic agent against chronic HBV infection.